c++ - Add value to array only if value isn't already in array -

my code far prevents more 2 duplicates, reason, allow 2 values same.

if (found != string::npos && binarysearch(wrongletters, used, guessletter) == -1)     {         wrongletters[turnnumber] = toupper(guessletter);         (int = 0; < guessword.length(); i++)         {             if (guessword[i] == guessletter)                 maskedword[i] = guessletter;         }     }     else if (found != string::npos && binarysearch(wrongletters, used, toupper(guessletter)) != -1)         cout << "that letter has been used\n\n";     else if (found == string::npos && binarysearch(wrongletters, used, toupper(guessletter)) != -1)         cout << "that letter has been used\n\n";     else if (found == string::npos && binarysearch(wrongletters, used, guessletter) == -1)     {         wrongletters[turnnumber] = toupper(guessletter);         cout << guessletter << " not in word guess\n\n";         incorrectcount++;     } 

if using namespace std, suggest following:

bool check = find(begin(array), end(array), x) != end(array); 

if x not found, find return location of 1 past last place checked.

if(!check)    *add element* 

if dynamic, suggest using vectors.